Within a view function is there a way to return a string along with a response object?

Question

The following snippet send a file to the browser.

# Prepare selected file for download...
filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )

What if i want to print some lines before sending the file, as in:

# Prepare selected file for download...
pdata = pdata + '''Your file will be ready for download'''
padata = pdata + '''it will just atake a moment'''

filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )

if i try to add pdata + reponse like:

return pdata + send_from_directory( filepath, filename )

i get an error that return should return a string only not string + response

this is in a function correct – vash_the_stampede Sep 20 '18 at 02:16 — vash_the_stampede, Sep 20 '18 at 02:16

score 2 · Answer 1 · answered Sep 20 '18 at 02:29

2

If you want to return a string and a response object both, try this:

return (pdata, send_from_directory(filepath, filename))

This will return a tuple with both datatypes within. You can't use a + symbol unless you've got 2 objects that are compatible, as an example, "string" + "string" or (tuple,) + (tuple,)

answered Sep 20 '18 at 02:29

UtahJarhead

2,091
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The outer `()` are redundant and not needed. It would also be good to indicate how to retrieve the elements at the caller. – Stephen Rauch Sep 20 '18 at 02:32
Although this solution seems very straightforward i get this `TypeError: Invalid status argument` – Νικόλαος Βέργος Sep 20 '18 at 02:34
Also if i try `return send_from_directory(filepath, filename), pdata` i get `ValueError: unicode object contains non latin-1 characters` – Νικόλαος Βέργος Sep 20 '18 at 02:46
@StephenRauch Well, I think i knew that, but I like explicitly wrapping them in parentheses just so I can see at a glance. To be honest, I've never tried it without. – UtahJarhead Sep 20 '18 at 15:29
@ΝικόλαοςΒέργος Errors you are getting don't have anything to do with the `return` statement. You're getting the error probably in the `send_from_directory()` function and the data isn't what is expected. – UtahJarhead Sep 20 '18 at 15:30
Yes, its that function that gives trouble because it cannot handle a filename having chars other that latin-iso. Cn you help me fix this? – Νικόλαος Βέργος Sep 20 '18 at 15:57
I'll assume `filename` is the improper string. try this if python2: `send_from_directory(filepath, str(filename, 'utf-8'))` You're probably not using python3 because string are already unicode by default, I think. – UtahJarhead Sep 20 '18 at 16:41

vash_the_stampede · Answer 2 · 2018-09-20T02:27:32.277

-1

Why not just print before you return?

def add(a, b):
    print(f"{a} is being added...")
    print(f"{b} is being added..")
    return a + b

c = add(1, 2)
print(c)

(xenial)vash@localhost:~/python/stack_overflow$ python3.7 strings.py
1 is being added...
2 is being added..
3

Suggest:

print(f'{pdata} "Your file will be ready for download..."')
print(f'{pdata} "it will just atake a moment..."')

filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )

Older Python:

print(f'{} "Your file will be ready for download..."'.format(pdata))
print(f'{} "it will just atake a moment..."'.format(pdata))

filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )

edited Sep 20 '18 at 02:27

answered Sep 20 '18 at 02:20

vash_the_stampede

4,590
1
8
20

Why only Python 3.6+? – Stephen Rauch Sep 20 '18 at 02:22
So Vash, in my code, how do you propose i write it? – Νικόλαος Βέργος Sep 20 '18 at 02:24
@StephenRauch for future reference, if I'm helping what if this format viable for older versions, as in `"{}",format(x)`, I just started programming this month so I only know of 3.6+, sorry – vash_the_stampede Sep 20 '18 at 02:25
Yes, go with `.format()` for best breadth. Python 2.7 is almost gone, but it will be with us a bit longer. More importantly many learners seem to still be using 2.7. – Stephen Rauch Sep 20 '18 at 02:26
@ΝικόλαοςΒέργος updated answer – vash_the_stampede Sep 20 '18 at 02:30
So, i can actually use print within a view function and then also use return? I though only in return i was supposed to reurn the whole html data back to the browser. – Νικόλαος Βέργος Sep 20 '18 at 02:35
@ΝικόλαοςΒέργος I would check the link posted for more information – vash_the_stampede Sep 20 '18 at 02:37
i did but this approach gives me this error `TypeError: Invalid status argument` Perhaps this is because the 2nd tuple elemnt is send_from_directory – Νικόλαος Βέργος Sep 20 '18 at 02:38

Within a view function is there a way to return a string along with a response object?

2 Answers2